Excess Heat Evolution During Electrolysis of H₂O with Nickel, Gold, Silver, and Tin Cathodes

Excess heat evolution was measured on nickel, gold, silver, and tin in aqueous K₂CO₃, Na₂CO₃, Na₂SO₄, and Li₂SO₄ solutions under galvanostatic electrolysis conditions. Steady evolution of excess heat in various electrode-electrolyte systems, but not in Ni/Na₂CO₃, Ni/Na₂SO₄, and Ni/Li₂SO₄, was observed for at least several days of observation. The largest excess heat observed was 907 mW on tin in K₂SO₄.